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Matthew B. Thomas Simon N. Wood Juergen Langewald Chris J. Lomer 《Pest management science》1997,49(1):47-55
The residual infectivity of an oil formulation of the fungal entomopathogen Metarhizium flavoviride was measured during a field trial against the rice grasshopper, Hieroglyphus daganensis, in north Benin. The pattern of infectivity was shown to decline exponentially following application, with a half-life of 6·8 days. In this environment, infections due to residual spores from the spray were identified as a key route of infection and accounted for 40–50% of the total infection measured 12 days after application. To examine the within- and between-season consequences of such residual infection, a simple host–pathogen model was developed. The model revealed that even very small increases in residual activity could provide large increases in total mortality and that under certain conditions, residual infection was essential for effective pest control. This aspect of the activity of mycopesticides is rarely considered. The implications of these results are discussed in the context of developing optimum spray strategies for locust and grasshopper control under different ecological conditions. © 1997 SCI. 相似文献
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- 1. The lacustrine brown trout (Salmo trutta) is endangered and of high conservation importance. In the only spawning habitat of the population in the Bavarian Lake Walchensee, the River Obernach, a substantial decrease in spawning runs has been reported. In this study, the present ecological state of the spawning stream was analysed with the objective of identifying life‐stage specific limitations to successful recruitment attributable to deficiencies in (i) spawning migration, (ii) spawning habitat quality, and (iii) habitat quality for juveniles.
- 2. Structural stream analysis showed that discharge and several migration barriers — particularly near the river outlet into the lake — prevent successful spawning migrations at normal water levels. Migration barriers are probably the main limiting factor for reproduction of lacustrine brown trout, whereas structural variability of the Obernach meets the habitat requirements of both spawners and juveniles.
- 3. Spawning site quality was suitable for trout, as indicated by stream substratum texture and high exchange rates between free‐flowing water and the interstitial zone in physico‐chemical parameters (redox potential, dissolved oxygen, pH, temperature and conductivity).
- 4. Analyses of fish community structure revealed dominance of lithophilic species, in particular of riverine brown trout (Salmo trutta). Its density and intact demographic population structure suggest that spawning and juvenile habitat quality for salmonids is not limiting. Recapture of stocked lacustrine trout juveniles also indicates habitat suitability for the juvenile stage.
- 5. In conclusion, the results show that the methodology used in this study is suitable for the identification of life‐stage specific habitat deficiencies in lacustrine brown trout and other fish species. Availability of habitat data throughout the species' distribution range is a first crucial step for the development of an effective recovery plan. Copyright © 2009 John Wiley & Sons, Ltd.
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Stefan Willför Andrey Pranovich Tarja Tamminen Juergen Puls Christiane Laine Anna Suurnäkki Bodo Saake Kati Uotila Helena Simolin Jarl Hemming Bjarne Holmbom 《Industrial Crops and Products》2009,29(2-3):571-580
Acid hydrolysis, acid methanolysis, and enzymatic hydrolysis were compared for depolymerization of five different plant materials containing uronic acids. The analyzed plant materials were oat spelt, wheat straw, spruce thermomechanical pulp, aspen stemwood, and totally chlorine-free (TCF) bleached hardwood kraft pulp. Furthermore, GC (using both HP-1 and HP-5 capillary columns and FID and MSD detectors), HPAEC-PAD, and HPAEC-Borate techniques were compared for subsequent analysis of the released monosaccharides. It was shown that acid methanolysis combined with GC analysis is a convenient method for obtaining the sugar unit composition and amount of non-crystalline polysaccharides in different plant materials. The methanolysis method was generally superior to the hydrolysis method for xylan- and uronic acid-containing samples. However, acid and enzymatic hydrolysis showed the highest recoveries for bleached chemical pulp samples. Acid hydrolysis is also required for crystalline polysaccharides, but the strong acid conditions evidently lead to degradation of labile sugars. The plant methanolysates were not suitable as such for analysis on an HPAEC-PAD system. For analysis of the total amount of sugar units, hence including cellulose, other non-crystalline hemicelluloses, and pectins, a combination of the methanolysis and hydrolysis methods is recommended. 相似文献
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Knoblich JA 《Science (New York, N.Y.)》2006,314(5802):1094-1096
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Within the European Union (EU)-funded Project ‘Wind Erosion on European Light Soils’ (WEELS), a model was designed and implemented with the aim of predicting the long-term spatial distribution of wind erosion risks in terms of erosion hours and wind-induced soil loss. In order to ensure wide applicability, the model structure consists of a modular combination of different approaches and algorithms, running on available or easily collected topographic and climatological data input. Whereas the ‘WIND’, ‘WIND EROSIVITY’ and ‘SOIL MOISTURE’ modules combine factors that contribute to the temporal variations of climatic erosivity, the ‘SOIL ERODIBILITY’, ‘SURFACE ROUGHNESS’ and ‘LAND USE’ modules predict the temporal soil and vegetation cover variables that control soil erodibility. Preliminary simulations over a 29-year period for the Barnham site (UK) (1970–1998) and a 13-year period for the Grönheim site (Germany) (1981–1993) generally resulted in a higher erosion risk for the English test site, where the total mean soil loss was estimated at 1.56 t ha−1 year−1 and mean maximum soil loss at about 15.5 t ha−1 year−1. The highest rates exceeded 3 t ha−1 in March, September and November. On the northern German test site, the total mean soil loss was 0.43 t ha−1 year−1. The highest erosion rates were predicted in April when they can exceed 2.5 t ha−1. The total mean maximum soil loss at this site of about 10.0 t ha−1 year−1 corresponds to a loss of about 0.65 mm. Predictions based on a land use scenario for the German site revealed that the erosion risk could be reduced significantly by changing land use strategies. 相似文献
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Baumeister W Bachmair A Chau V Cohen R Coffino P Demartino G Deshaies R Dohmen J Emr S Finley D Hampton R Hill C Hochstrasser M Huber R Jackson P Jentsch S Johnson E Kwon YT Pagano M Pickart C Rechsteiner M Scheffner M Sommer T Tansey W Tyers M Vierstra R Weissman A Wilkinson KD Wolf D 《Science (New York, N.Y.)》2004,306(5700):1290-1292
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Hamir AN Greenlee JJ Stanton TB Smith JD Doucette S Kunkle RA Stasko JA Richt JA Kehrli ME 《Canadian journal of veterinary research》2011,75(1):18-24
The primary objective of this study was to determine whether or not Spiroplasma mirum would be capable of producing lesions of transmissible spongiform encephalopathy (TSE) when inoculated in raccoons (Procyon lotor) and, if that was possible, to compare the clinicopathological findings with those of transmissible mink encephalopathy (TME) in the same experimental model. For this purpose, 5 groups (n = 5) of raccoon kits were inoculated intracerebrally with either S. mirum and/or TME. Two other groups (n = 5) of raccoon kits served as sham-inoculated controls. All animals inoculated with TME, either alone or in combination, showed clinical signs of neurologic disorder and were euthanized within 6 mo post-inoculation (MPI). None of the carcasses revealed gross lesions. Spongiform encephalopathy was observed by light microscopy and the presence of abnormal disease-causing prion protein (PrP(d)) was detected by immunohistochemistry (IHC) and Western blot (WB) techniques in only the raccoons administered TME. Raccoons inoculated with Spiroplasma, but not administered TME agent, were euthanized at 30 MPI. They did not show clinical neurologic signs, their brains did not have lesions of spongiform encephalopathy, and their tissues were negative for S. mirum by polymerase chain reaction (PCR) and for PrP(d) by IHC and WB techniques. The results of this study indicate that Spiroplasma mirum does not induce TSE-like disease in raccoons. 相似文献
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Longwood花园的郁金香花展是自1921年以来一直流传下来的传统。在11月到翌年4月期间,温室里进行的盆栽郁金香花展非常引人注目。盆栽郁金香种植促成盆栽郁金香,首先应该选择高质量的种球,其级别是12+级即球根的周长是12cm或者更大,这个级别对 相似文献